From patchwork Mon Mar 8 12:30:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 395919 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 044B0C432C3 for ; Mon, 8 Mar 2021 12:32:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D767C64EBC for ; Mon, 8 Mar 2021 12:32:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230327AbhCHMbg (ORCPT ); Mon, 8 Mar 2021 07:31:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:40666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229899AbhCHMb2 (ORCPT ); Mon, 8 Mar 2021 07:31:28 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8685364EBC; Mon, 8 Mar 2021 12:31:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615206688; bh=JWcP2Ez3OrVt5pwP1x7P4o15l+tIK0bYpn4uFy4OUO8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EJb6PHs0IvnFJ3XE0woLLFzg80Y6sbz+FYdPt8UhXlXq/aphGbH16yrv4oURWiriH SeIYGiffxBvZ0nSuIfIu4K9pGRGGxSMJY62Ebm6Gfd7dDHm7nX9KI/2aB3lSxRpDHU 1Pp3E31fyAvszh5QqAdmXruyZGhb4H+P7XNSijgo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Thumshirn , David Sterba Subject: [PATCH 5.4 03/22] btrfs: raid56: simplify tracking of Q stripe presence Date: Mon, 8 Mar 2021 13:30:20 +0100 Message-Id: <20210308122714.563884205@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210308122714.391917404@linuxfoundation.org> References: <20210308122714.391917404@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Sterba commit c17af96554a8a8777cbb0fd53b8497250e548b43 upstream. There are temporary variables tracking the index of P and Q stripes, but none of them is really used as such, merely for determining if the Q stripe is present. This leads to compiler warnings with -Wunused-but-set-variable and has been reported several times. fs/btrfs/raid56.c: In function ‘finish_rmw’: fs/btrfs/raid56.c:1199:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable] 1199 | int p_stripe = -1; | ^~~~~~~~ fs/btrfs/raid56.c: In function ‘finish_parity_scrub’: fs/btrfs/raid56.c:2356:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable] 2356 | int p_stripe = -1; | ^~~~~~~~ Replace the two variables with one that has a clear meaning and also get rid of the warnings. The logic that verifies that there are only 2 valid cases is unchanged. Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/raid56.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -1198,22 +1198,19 @@ static noinline void finish_rmw(struct b int nr_data = rbio->nr_data; int stripe; int pagenr; - int p_stripe = -1; - int q_stripe = -1; + bool has_qstripe; struct bio_list bio_list; struct bio *bio; int ret; bio_list_init(&bio_list); - if (rbio->real_stripes - rbio->nr_data == 1) { - p_stripe = rbio->real_stripes - 1; - } else if (rbio->real_stripes - rbio->nr_data == 2) { - p_stripe = rbio->real_stripes - 2; - q_stripe = rbio->real_stripes - 1; - } else { + if (rbio->real_stripes - rbio->nr_data == 1) + has_qstripe = false; + else if (rbio->real_stripes - rbio->nr_data == 2) + has_qstripe = true; + else BUG(); - } /* at this point we either have a full stripe, * or we've read the full stripe from the drive. @@ -1257,7 +1254,7 @@ static noinline void finish_rmw(struct b SetPageUptodate(p); pointers[stripe++] = kmap(p); - if (q_stripe != -1) { + if (has_qstripe) { /* * raid6, add the qstripe and call the @@ -2355,8 +2352,7 @@ static noinline void finish_parity_scrub int nr_data = rbio->nr_data; int stripe; int pagenr; - int p_stripe = -1; - int q_stripe = -1; + bool has_qstripe; struct page *p_page = NULL; struct page *q_page = NULL; struct bio_list bio_list; @@ -2366,14 +2362,12 @@ static noinline void finish_parity_scrub bio_list_init(&bio_list); - if (rbio->real_stripes - rbio->nr_data == 1) { - p_stripe = rbio->real_stripes - 1; - } else if (rbio->real_stripes - rbio->nr_data == 2) { - p_stripe = rbio->real_stripes - 2; - q_stripe = rbio->real_stripes - 1; - } else { + if (rbio->real_stripes - rbio->nr_data == 1) + has_qstripe = false; + else if (rbio->real_stripes - rbio->nr_data == 2) + has_qstripe = true; + else BUG(); - } if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) { is_replace = 1; @@ -2395,7 +2389,7 @@ static noinline void finish_parity_scrub goto cleanup; SetPageUptodate(p_page); - if (q_stripe != -1) { + if (has_qstripe) { q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!q_page) { __free_page(p_page); @@ -2418,8 +2412,7 @@ static noinline void finish_parity_scrub /* then add the parity stripe */ pointers[stripe++] = kmap(p_page); - if (q_stripe != -1) { - + if (has_qstripe) { /* * raid6, add the qstripe and call the * library function to fill in our p/q